A U.S. Air Force non-destructive inspection apprentice assigned to the 1st Maintenance Squadron inserts a boat into an optical emission spectrometer before analyzing aircraft oil at Langley Air Force Base, Va., Sept 22, 2015. The analysis of aircraft oil by U.S. Service members follows standards set forth by the Joint Oil Analysis Program. (U.S. Air Force photo by Senior Airman Aubrey White/Released)